Electric heating system.



L. P. HYNES.

ELECTRIC HEATING SYSTEM.

APPLICATION FILED MAY 5. 1913. RENEWED JAN. 26. 1916.

1, 1 80,85 1 Patented Apr. 25, 1916.

2 SHEETS-SHEET I.

L. P. HYNES.

ELECTRIC HEATING SYSTEM. APPLICATION FILED MAY 5. I9I3- RENEWEDJAN.26.1916.

Patented Apr. 25,1916.

2 SHEETS-SHEET 2.

UNITED STATES FAT NT FFICE LEE JP. HYNES, OF CHICAGO, ILLINOIS, ASSICNORTo RAILWAY UTILITY COMPANY, OE

CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

ELECTRI HEATING SYSTEM.

Specification of Letters Patent.

Patented Apr. 25, 1916.

Application filed May 5, 1913, Serial NO. 765,547. Renewed January 26,1916. I Serial NO. 74,475.

which a heavy heating current may be employed and yet be controlled by avery delicate thermostat which operates with slight fication, but it isthe purpose of exemphficavariationsin temperature and cannot besubjected to the flow of a heavy current without injury.

A. further object is to provide control mechanism which can beconveniently grouped upon a suitable panel board and the members ofwhich can be readily replaced or exchanged when worn out or to suitchanged conditions of operation.

A preferred form of my inventlon 1s illus trated in the accompanyingdrawings and specifically described in the following specito beunderstood that this disclosure is for tion only and that the scope ofthe invention is to be determined from the following claims in which Ihave endeavored to set forth my invention in such terms as todistinguish it from the prior art so far as known to me without,however, relinquishing or dedicating any portion thereof.

In the accompanying drawings, F1gure 1 represents a panel board uponwhich various members of my system are mounted, one of the latter beingpartly in section; Fig. 2 is a view in elevation perpendicular to theplane of Fig. 1 and looking in the direction of the arrow 2; Fig. 3 is asimilar view but looking in the direction of the arrow 3 (Fig. l) andFig 4 isa dlagram of the parts and their connectlons.

'The same reference numeral is applied to each part wherever it occursin the several views.

Referringfirst to the diagram Fig. 4c, the leads for the heating systemare shown at 5 and 6, the heating coils at A and the switch for closingthe circuit through the same at 7. A magnet 8 for Operating the switchis county of Cook, State of Illinois, have in shunt to the heatingcircuit and included in circuit with a resistance 9 and an auxiliaryresistance 10 of cartridge form is also inserted in the circuit for apurpose to be presently described, with one head between clips 11, 12 onthe panel board and the other head between the clips 13, 14, each of theclips 11, 12, 13 and 14 being insulated from the others but all of thembeing electrically connected when the resistance 10 is in place. Clip 12is electrically connected to magnet 8 and clip 14 is grounded by wire14:. There is thus established through the magnet and resistances apermanently closed circuit Whenever the system is connected to themains, which tends to hold switch or contactor 7 closed. A- secondarycircuit which is in shunt both to the heating circuit and. to the circutthrough the switch operating magnet 8 for controlling the current in thelatter, comprises the connectingwire 15, contacts 16, 17, and wire 18,the last connecting to the clip 12. The contacts 16 and 17,'of whichcontact 16 is spring actuated to separate the pair, are controlled by anelectro-magnetic means 19 which is in Shunt to the auxiliary resistance10, the connection being from the contact clip 11, abovementioned,through fuse 20, coil 19, wire 21, thermostat 22, wire 23, andContact clip 13.

shown thermostat 22 is of the thermometer type.

lit will now be understood that under normal working conditions acurrent will flow from lead 5, throughv resistance 9, the coil of magnet8, contact 12, resistance 10, contact 14, and to earth, thus keeping thecontact member 7 normally closed, and the heating current on. Underthese conditions, the temperature being below the critical, the circuitthrough the fuse 20, coil 19 and thermostat 22 is open and consequentlythe contacts 16 and 17 are open. When, however, the temperature risessutiiciently to cause the thermostat 22 to close the cir cuit throughthe coil 19, the latter operates to close the contacts 16, 17, thusshort-circuiting the magnet 8 through the following path: fromresistance 9 through wire 15, contacts 16, 17, wire 18, contact 12,resistance 10 and contact 1 and to earth. The resistance of this shuntis such that when closed, the current through the magnet coil 8 isreduced to such an extent that it re- This condition exists until thetemperature of the apartment in which the thermostat 22 is located fallsto such degree that the thermostat opens the circuit through the coil19. The latter then permits the contacts 16 and 17 to separate, thusopening the shunt around the coil 8 when the entire current through theresistance 9 passes through the latter, and being of sufficient strengthto close the switch 7 the heating current is again effective. Thecurrent through the thermostat in this system may be made as small asdesired by proportioning the resistance of the shunt circuit in which itis contained to the resistance 10 with which it is in circuit; and it isfurther protected by the fuse 20:

The arrangement of the apparatus for practical use is shown in Figs. 1,2, and3. The resistance 9, as shown in Figs. 1, 2, and 3, is of aremovable cartridge type, being received by spring clips 24 engaging theopposite ends thereof-and the fuse 20 is of similar construction, andsimilarly held. The resistance 10 is also of the cartridge type but, asheretofore stated, the clips 11, 12, 13, 14 which it engages areinsulated from each other, so that in the event that either end of theauxiliary resistance 10 is removed from contact with its clips, nodestructive current can pass through the thermostat to the injury of thelatter and obviously, when said resistance is in place, the thermostatis protected thereby. The particular construction of theelectro-magnetic means carrying and controlling the contacts 16, 17 isbest shown by reference to Fig. 1. A casing 25 of insulating materialcontains amagnet 26 having a surrounding field 27 and a hollow corethrough which passes a rod 28 of non-conductlng material. At its upperend said rod is adapted to engage the spring contact. 16 and operate thesame, and at its lower end. rests upon the armature29 of the magnetwhich is in the end of a plate guided by adjustable screws 30, 31. Theinsulating boxing 25 carries four contact plugs 33, 34, 35 and 36 ofwhich diagonally opposite plugs 34 and 35 are connected to the leads ofthe coil 26, and plugs 33, 36 are connected to the spring and stationarycontact members respectively. The clip 37 which receives the plug 34 isconnected to the adjacent fuse receiving clip, and the clip 38 whichreceives plug 35 is connected to the wire 21 which leads to thethermostat. Clip 39 which receives the plug 33 is connected to the clip24 of the resistance 9 while clip 40 which receives plug 36 is connectedto clip 12 of the auxiliary secondary resistance 10. It follows fromthis diagonal arrangement and connection of the plugs that if the casing25 be carelessly reversed when placed in the clips, no-harm can resultto the more delicate portions of theapparatus, by the passage ofacircuit therethrough which they are not intended to receive. Thecontactor may be of any usual or approved type and is permanentlyaffixed to the panel board in any desired manner. The form of contactorshown comprises an electro-magnet 41, the armature 42 of which ispivoted at 43 and carries the movable contact 44 which is normally heldin electrical contact with the stationary contact member 45 by the coil41. But when the current through the electromagnet is reduced, as statedabove, the contactoris opened by the tension spring 46. As above statedthis construction being a common one in the art, need not be furtherdescribed.

I claim:

1. In an electric heatingsystem, a heating circuit including a switchtherefor, electro-magnetic means 8 for holding the switch closed, ashunt around said electromagnetic means comprising the contacts 16, 17.,electro-magnetic means 19 for controlling said contacts, a thermostaticcut-out 22 in series with electro-magnetic means 19, a pair of clips 11,12 insulated from each other, clip '11 being in electrical connectionwith. the electro-magnetic means 19 and the cut-out 22, and clip 12 inelectrical connection with the electro-magneticmeans 8, a pair of clips13,14 connected to ground and to the cutout 22 respectively, and aresistance 10 inserted between the pair of clips 11, 12 and the pair ofclips 13, 14.

2. In an electric heating system, a heating circuit including aswitchtherefor, electros magnetic means 8 for holding the switch closed,a shunt about said electro-magnetic means comprising the contacts 16,17, electro-magnetic means 19 for controlling said contacts, athermostatic cut-out 22 in circuit with electro-magnetic means 19, apair .of clips 11, 12, the members of which are connected to theelectro-magnetic means 8 and electro-magnetic means 19, respectively, apair of clips 13, 14, the members of which are insulated from each othergand one of which is connected to ground and the other to the cut-out22, and a resistance 10 interposed between said clips. I

3. In an electric heating system, a heating circuit including a switchtherefor, electromagnetic means 8 for holding the switch closed, a shuntabout said electro-magnetic means comprising the contacts 16, 17,electro-magnetic means 19 for controlling said contacts, a thermostaticcut-out 22 in circuit with electro-magnetic means 19, a pair of clips11, 12 insulated from each other and connected respectively to theelectro-magnetic means 19 and to the electro-magnetic means 8, a pair ofclips 13, 14- the members of which are insulated from each other andconnected respectively to the cut-out 22 and to ground, and a resistance10 inserted between said clips.

4. In an electric heating system for cars and the like, a heatingcircuit having a switch for controlling the same, an electromagneticmeans for controlling the switch, a circuit including said means andresistance, a shunt about said electro-magnetic means comprising anormally open switch, a thermostatically controlled circuit in shunt tosaid resistance and including electro-magnetic means for closing saidswitch, said resistance being connected to a pair of uncon nectedterminals at each end, the two terminals at one end being connectedrespectively to the electromagnetic means for operating the main switchand the electro-magnetic means for operating the other switch, and theterminals at the other end of said resistance being connectedrespectively to the thermostatically controlled circuit and the returnmain.

5. In an electric heating system for railway cars and the like, aheater, a connection for said heater to a source of current, anelectromagnetic contactor in said connection for opening and closing thesame, said contactor having a single operating coil, a cir- LEE P.HYNES. Witnesses:

JOHN B. MACAULEY, ROBERT DOBBERMAN.

